The present invention relates to a method of manufacturing a semiconductor integrated circuit device, a method of manufacturing a photomask and a photomask technique, particularly to a technique useful for photolithography (referred to merely as lithography hereinafter) in which a given pattern is transferred to a semiconductor wafer (referred to merely as a wafer hereinafter) by exposure treatment using a photomask (referred to merely as a mask hereinafter) in the process of manufacturing a semiconductor integrated circuit device.
An ordinary mask used in lithography technique is a member in which a shading pattern made of a metal film, such as a chromium film, is made on a mask substrate in a planar, rectangular form. However, the mask having this structure has a problem that costs thereof are high since the number of mask-producing steps is large and a problem that processing dimensional accuracy is lowered since the shading pattern is processed by isotropic etching. As proposal to avoid such problems, for example, Japanese Patent Laid-Open Publication No. 5-289307 discloses a technique in which the fact that about a given resist film its transmissivity of ArF excimer laser can be made to 0% is used and a shading pattern on a mask substrate is made of the resist film.
However, the present inventors have first found out that the above-mentioned mask technique in which the resist film is used as the shading pattern has the following problems.
First, in the case that the planar shape of the mask substrate of the mask in which the resist film is used as the shading pattern is made to a rectangular shape, very small residues of the resist film, released from the mask substrate, bounce off walls of a developing unit around the mask substrate when the resist film is developed and washed with the mask substrate being rotated in the principal plane thereof. The residues are then adhered to the principal plane of the mask, particularly the vicinity of the corners of the mask substrate, again. The adhered alien substances function as shading substances in the mask in which the resist film is used as a regular shading body. Therefore, if this mask is used to transfer the regular pattern onto a wafer, defects are also transferred.
Second, there remains a problem that the matter that costs of the mask are to be further lowered had not been taken into sufficient consideration. In recent years, costs of masks have been increasing in semiconductor integrated circuit devices. This is based on the following reasons. Since market scale is small in the field of mask-producing devices, masks are unprofitable. In such a situation, developing costs or running costs of drawing devices for forming a pattern on a mask or examination devices of examining the pattern become far higher as the pattern formed on a mask becomes finer and denser. To collect costs for this, mask costs must be made high. With an improvement in performance of semiconductor integrated circuit devices, the total number of masks necessary for producing one semiconductor integrated circuit device trends to increase. From this viewpoint, a reduction in mask costs is also an important theme.
The present inventors researched known examples of a mask on the basis of results of the present invention. As a result, for example, Japanese Patent Laid-Open Publication Nos. 11-212250 and 6-19121 disclose the following technique: in an ordinary mask using a metal film made of chromium or the like as a shading pattern, the planar shape of a mask substrate is made to a circular shape in order to improve the uniformity of a resist film for patterning the metal film.
For example, Japanese Patent Laid-Open Publication Nos. 9-120986 and 9-8103 disclose an aliment technique performed when a circular mask substrate of an ordinary mask in which a metal film made of chromium or the like is used as a shading pattern is set to an exposure device.
For example, Japanese Patent Laid-Open Publication No. 6-176408 discloses an exposure technique in which a circular substrate is exposed to light through a pattern of a circular mask.
For example, Japanese Patent Laid-Open Publication No. 5-335203 discloses a technique in which a large chip pattern is arranged on a circular mask substrate.
For example, Japanese Patent Laid-Open Publication No. 2-82244 discloses a technique of mark arrangement performed when a mask substrate is made circular.
An object of the present invention is to provide a technique making it possible to improve reliability of a mask.
Another object of the present invention is to provide a technique making it possible to improve the yield of semiconductor integrated circuit devices.
A further object of the present invention is to provide a technique making it possible to reduce costs for producing a mask.
The above-mentioned objects and other objects of the present invention, and new features thereof will be apparent from the description of the present specification and attached drawings.
A summary of typical aspects of the present invention disclosed in the present application is as follows.
According to the present invention, the planar shape of a mask substrate of a mask having a formed shading pattern composed of an organic film having the property of blocking off light for exposure is made circular.
The present invention comprises the step of forming a shading pattern composed of an organic film having the property of blocking off light for exposure on a mask substrate having a planar circular shape.
According to the present invention, in the outer circumferential end portion of the mask substrate having the planar circular shape, an edge of a first principal plane where the shading pattern composed of the organic film is formed is more largely chamfered than that of a second principal plane reverse to the first principal plane.
The present invention comprises the step of transferring the same patterns onto different areas of the mask substrate having the planar circular shape when the given pattern is transferred on the mask substrate, the step of using the photomask having the shading pattern composed of the organic film to expose a light-sensitive resin film on a substrate to be processed to light, and the step of comparing the same patterns transferred onto the different areas in the substrate to be processed with each other, to examine the quality of the pattern of the photomask.
According to the present invention, the diameter of the mask substrate having the planar circular shape is equal to or smaller than that of a substrate to be processed which is exposed to light using the mask substrate.
According to the present invention, a processing device for the mask substrate having the planar circular shape and a processing device for the semiconductor wafer are made common.
A summary of typical other aspects of the present invention disclosed in the present application is as follows.
According to the present invention, when an integrated circuit pattern is formed on a wafer, a laser beam or an electron beam is used to form an enlarged circuit pattern of a resist film on a transparent circular mask substrate, and then the resist pattern is used as a shading film to perform scale-down projective exposure using transmissible light from the mask, thereby transferring the integrated circuit pattern onto the semiconductor wafer.
According to the present invention, when an integrated circuit pattern is formed on a wafer, a phase shift pattern layer for reversing the phase of transmissible light and a resist shading pattern layer for blocking off the transmissible light are formed on a transparent circular mask substrate, and the transmissible light from the mask is used to perform scale-down projective exposure, thereby transferring the integrated circuit pattern onto the wafer.
The present invention, the resist is made to a monolayer structure of a chemically-sensitizing type resist or a bilayer structure having an antireflection film and a chemically-sensitizing type resist.
The present invention is a method of manufacturing a mask for scale-down projective exposure, comprising applying a resist onto a circular mask substrate, and using a laser beam or an electron beam to perform circuit-pattern exposure. The resist film is developed by combining rotation of the circular mask substrate with movement in the radial direction of the dropping and supplying position of a resist developing solution onto the circular mask substrate so as to spread the developing solution all over the substrate, and then rotating the circular mask substrate.
According to the present invention, after the developing treatment, the end face of the circular mask substrate and the back surface thereof are washed.
The present invention is the method of manufacturing the mask for scale-down projective exposure, wherein a developed pattern of the resist film is formed on the transparent circular mask substrate, the circular mask substrate is immersed into a washing solution, and subsequently the circular mask substrate is rotated, thereby performing developing and washing treatments.
According to the present invention, a chemically-sensitizing type resist is used as the resist, and an alkaline developing solution is used as the developing solution.
The present invention comprises the step of:
forming a shielding metal film on a circular transparent glass substrate,
forming a window for an integrated circuit pattern transferring area on the circular transparent glass substrate and making an alignment mark for forming the integrated circuit pattern and an alignment mark for a scale-down projective exposure device therein,
using the alignment mark to form an enlarged resist circuit pattern on the circular transparent glass substrate, and
using the resist on the circular transparent glass substrate as a shading film for blocking off light for exposure to perform scale-down projective exposure, thereby transferring a circuit pattern onto a wafer.
The present invention comprises the step of:
forming a shielding metal film on a circular transparent glass substrate,
forming a phase shift pattern, which is one of integrated circuit patterns, on the circular transparent glass substrate and making an alignment mark for forming the integrated circuit patterns and an alignment mark for a scale-down projective exposure device therein,
using the alignment mark to form an enlarged resist circuit pattern on the circular transparent glass substrate, and
using the resist on the circular transparent glass substrate as a shading film for blocking off light for exposure to perform scale-down projective exposure, thereby transferring a circuit pattern onto a wafer.
According to the present invention, the resist circuit pattern formed on the circular transparent glass substrate by using the alignment mark is composed of the same patterns, and the mask pattern is examined by comparison-examination of the patterns transferred on the wafer.
The present invention is a manner in which at the time of producing an integrated circuit device, a laser beam or an electron beam is used to form an enlarged circuit pattern on a circular mask substrate, and then transmissible light from the circular mask substrate is used to perform scale-down projective exposure, thereby transferring a scale-down circuit pattern onto a wafer. The diameter of the circular mask is made equal to or smaller than that of the wafer.
According to the present invention, in the circular mask substrate, an edge of a principal plane of the end face of the substrate is largely chamfered. While the circular mask substrate is rotated, the mask substrate is subjected to developing treatment, and then the end face of the substrate and the back surface thereof are washed, thereby forming an enlarged circuit pattern on the substrate. The resultant product is used for transfer onto the wafer.